2, 2-dicyano-1-1-[(trisubstituted ammonium) alkoxy] ethenolates and their preparation



United States Patent 2,721,206 2,2 DICYANO 1 1 [(TRISUBSTITUTED AM-MONIUM)ALKOXY]ETHENOLATES AND THEIR PREPARATION William JosephMiddleton, Wilmington, Del., assignor to E. I. du Pont de Nemours andCompany, Wilmington, Del., a corporation of Delaware No Drawing.Application July 1, 1954,

SeriaI.No. 440,865 8 Claims. (Cl. 260-4654) This invention relates'toorganic compounds and their preparation and, more particularly, to a newclass of ethenolates and a process of preparing same.

An object of the present invention is to provide a new class ofethenolates. A further object is to provide a process of preparing suchcompounds. Other objects will be apparent from the description of theinvention given hereinafter.

The above objects are accomplished according to the present invention byreacting Z-dicyanomethylene cyclic 1,3-acetals with at leastsubstantially molecular equivalent amounts of tertiary amines to form2,2-dicyano-l-[(trisubstitutedammonium)alkoxy]ethenolates. Theseethenolates constitute a new class of compounds.

Copending application Ser. No. 416,720 filed March 16, 1954, in thenames of R. E. Heckert and W. J. Middleton, assigned to the assignee ofthe present application, discloses the preparation of 2-dicyanomethylenecyclic 1,3-acetals. More particularly, these acetals are substituted orunsubstituted Z-dicyanomethylene-1,3-dioxolanes and -dioxanes. They canbe prepared by dissolving tetracyanoethylene in an excess of a dihydricalcohol, adding a catalyst, and heating the solution to boiling untilthe dark color characteristic of the solution of tetracyanoethylene inthe alcohol is dispelled. The mixture is then cooled and theZ-dicyanomethylene-1,3-aceta1s crystallize out. The catalyst is used inamounts not exceeding 50 mol per cent, based on the tetracyanoethylene,and the catalyst can be practically any salt of a metal, e. g., ferricchloride or zinc acetate, or urea, or a tertiary amine such astriethylamine or pyridine.

Tetracyanoethylene, used in the preparation of the 2- dicyanomethylenecyclic 1,3-acetals, can be prepared by the reaction of sulfurmonochloride with malononitrile.

It has now been discovered that when these Z-dicyanomethylene cyclic1,3-acetals are reacted with at least substantially molecular equivalentamounts of a tertiary amine, i. e., at least substantially 1 mol ofamine to 1 mol of Z-dicyanomethylene cyclic 1,3-acetal, the formation ofa 2,2-dicyano-1-l (trisubstitutedamrnonium) alkoxy] ethenolate resultsand this may be readily isolated.

These ethenolates are meso-ionic compounds (Baker et al., l. Chem. Soc.1949, 310) in that they are not well represented by an ordinary covalentstructural formula but are more accurately portrayed as resonancehybrids of more than one ionic formula, as follows:

III

2,721,206 Patented Oct. 18, 19 55 For example, the infrared absorptionspectrum of 2,2-dicyanol 2- (trimethylammonium) ethoxy] ethenolate I (I)gives strong evidence of a carbon-to-carbon double bond though somewhatmodified, as if by the presence of a carbonyl bond. This indicates that,while (I) is the predominant form, the negative charge is probablystabilized by other resonance forms which possess a carbonyl structure(II and Ill).

It will be noted from (I) that the compounds of the present inventionare also related to the betaines in that they possess a positivelycharged amino function and a negatively charged oxygen atom.

The 2,2-dicyano-1-[ (trisubstitutedammonium) alkoxy] ethenolates arestable, white crystalline solids characterized by relatively highmelting points. They are very soluble in hot water, but are onlyslightly solublein cold water and organic solvents.

The process of the present invention involves the reaction of aZ-dicyanomethylene cyclic 1,3-acetal with at least a substantiallyequimolecular quantity of a tertiary amine. The cyclic acetal can beused as such or can be prepared in situ by starting with a mixture oftetracyanoethylene, a glycol, and a tertiary amine as in Example X. Thecyclic acetal which forms from tetracyanoethylene and the glycol underthese conditions reacts with the tertiary amine to yield the ethenolatewithout the necessity of isolating the cyclic acetal.

The necessity of using at least a substantially molecular equivalentamount of a tertiary amine in the preparation of the ethenolates of thisinvention is primarily based on practical considerations. That is, whenusing'a preformed cyclic acetal, the presence of less than a molecularequivalent amount of the tertiary amine, does not mean that no2,2-dicyano-l trisubstitutedammonium alkoxy] ethenolate is formed butrather that all of the acetal is not used up which, in addition to beinginefiicient in itself, greatly complicates the isolation ofuncontaminated 2,2-dicyano-l-E (trisubstitutedammonium) alkoxy]ethenolate, an otherwise quite simple operation. Further, when thecyclic acetal is prepared in situ by starting with tetracyanoethyleneand an excess of glycol (to insure full use of the tetracyanoethylene)and a substantial amount of tertiary amine is present but appreciablyless than 1 mol per mol of tetracyanoethylene, some2,2-dicyano-1-[(trisubstitutedammonium)alkoxyiethenolate will be formed,at least on prolonged heating, but here again isolation is difiicult andthere will be far from complete conversion of the cyclic acetal.

In a preferred embodiment of this invention, an equimolecular mixture ofdicyanoketene ethylene acetal (alternately namedZ-dicyanomethylene-l,3-dioxolane) and trimethylamine is dissolved inacetone or tetrahydrofuran and allowed to stand at room temperature for12 to 18 hours. 2,2 dicyano-l-[Z-(trimethylammonium)ethoxy] ethenolateseparates as a white crystalline solid which is collected by filtration.It may be purified by washing with diethyl ether and recrystallized fromwater. i

The following examples wherein all proportions are by weight unlessotherwise stated, illustrate specific embodiments of the invention. Allpercentage yields given are based on the amount of the cyclic acetalemployed.

EXAMPLE I A solution of 136 parts of dicyanoketene ethylene acetal in444 parts of tetrahydrofuran is saturated with trimethylamine and thewhite precipitate which forms is collected on a filter, washed withether and recrystallized from water. There is obtained parts (63%) of2,2- dicyano-l- [2- (trimethylammonium ethoxy] ethenolate in the form ofwhite prisms, M. P. 210-212 C.

Anal.Calcd. for CsHrsNsOz: C, 55.37; H, 6.71; N,

a 3 21.53. Found: C, 55.59, 55.68; H, 6.86, 6.84; N, 21.62, 21.64.

EXAMPLE II 'A solution of 101 parts of triethylamine and 136 parts of'dicyanoketene ethylene acetal in 444 parts of tetrahy drofuran isallowed to stand at room temperature for minutes. The .white precipitatewhich forms is collectedon a filter, washed with ether andrecrystallized from water. Thereis obtained 230 parts (97%) of 2,2-dicyano- 1- [2 (triethylammonium)ethoxy] ethenolate in the form of awhite crystalline solid, M. P..184186 C.

AnaL-Calcd. for C12H19N3O25-C, 60.74; H, 8.07; N, 17.71.. Found: C,60.85, 61.07; H, 8.14, 8.03; N, 17.25, 17.58.

EXAMPLE III A solution of 1360 parts of dicyanoketene ethylene acetal-in8880 parts of tetrahydrofuran is mixed with 2134 parts of distilleddimethyldodecylamine. The solution is allowed to stand for 24 hours anda seed crystal is prepared by evaporating a small portion of thesolution and vigorously scratching the viscous residue between glasssurfaces. The main reaction mixture is diluted with ether and the seedcrystal is added. The white precipitate which forms is recrystallizedfrom alcohol-ether. There is obtained 2500 parts (72%) of 2,2-dicyano-1-[2-(dimethyldodecylammonium) ethoxy] ethenolate in the form of whiteneedles, M. P. 70 C.

Anal.--Calcd. for CH35N3O22 C, 68.73; H, 10.09; N, 12.02. Found: C,68.95, 68.87; H, 10.11, 10.45; N, 12.12,

a EXAMPLE IV A solution of 165 parts of quinoline and 136 parts ofdicyanoketene ethylene acetal'in 440 parts of tetrahydrofuran is allowedto stand overnight at room temperature. The yellow precipitate whichforms is collected on a filter, washed with ether and recrystallizedfrom about 100,000 parts of water. There is obtained 200 parts (76%) of2,2-dicyano-1- [2-( l-quinolinium ethoxy]ethenolate in the form ofyellow crystals, M. P. 239-242" C.

Anal.Calcd. for C15H11N3O2: C, 67.91; H, 4.18; N, 15.84. Found: C,67.88, 67.90; H, 4.36, 4.43; N, 15.91, 15.87.

This ethenolate departs from the general rule in being yellow in colorrather than white in crystalline form.

EXAMPLE V A solution of 197 parts of pyridine and 272 parts ofdicyanoketenc ethylene acetal in 888 parts of tetrahydro- V furan isallowed to stand at room temperature for 10 Part A1-(2-hydroxyethyl)pyridinium Reineckate is prepared as follows.

A solution or 3.54 g. 0.01 mole) of Reinecke salt (NH4[Cr(CNS)4(NH3)2])in 50 ml. of water is mixed with a solution of 1.6 g. (0.01 mole) of1-(2-hydroxyethyl)-pyridinium chloride (Barnes and Adams, I. 'Am.

Chem. Soc. 49, 1311-12 (1927)) in ,10 ml. of water. The

Reineckate in the form of lavender flakes, M. P. 186-192 C. withdecomposition.

Anal.-Calcd. for C11H16N'7S4OC1; C, 29.85; H, 3.66;

N, 22.15. Found: C, 30.14; H, 3.82; N, 22.20, 22.24.

Part B 2,2 dicyano 1 [2-(l-pyridinium)ethoxylethenolate, 2.15 g. (0.01mole), is dissolved in 20 ml. of 5N hydrochloric acid and the solutionis heated under reflux for 30 minutes. This solution is cooled and mixedwith a filtered solution of 3.54 g. (0.01 mole) of Reinecke salt in 50ml. of water. The pink precipitate which forms is collected on a filter,washed with water and recrystallized from acetone-water. There isobtained 4 g. of 1-(2- hydroxyethyl) pyridinium Reineckate in theformoflavender flakes, M. P. 186189 C. The X-ray diffraction pattern andinfrared absorption spectrum of this product are identical with those ofthe 1-(2-hydroxyethyl)pyridinium Reineckate prepared from1-(2-hydroxyethyl)- pyridinium chloride as described in Part A.

EXAMPLE VI A solution of parts of alpha-picoline and 136 parts ofdicyanoketene ethylene acetal'in 888 parts of tetrahydrofuran is allowedto stand overnight at room temperature. The White crystallineprecipitate which'forms is collected on a filter, washed with ether andrecrystallized from water. There is obtained 150 parts (66%) of 2,2dicyano l-[l-(alpha-picolinium)ethoxy]ethenolate in the form of whiteplates, M. P. 175 C.

Anal.-Calcd. for C12H11N3O2: C, 62.87; H, 4.95; N, 18.33. Found: C,62.93, 63.15; H, 5.10, 4.94; N, 18.42,

EXAMPLE VII Alpha-bromopyridine, 249 parts, is added to a .solution of136 parts of dicyanoketene ethylene acetal in 444 parts oftetrahydrofuran. T he'solid which separates after standing for one weekis collected on a filter, washed with ether and recrystallized fromwater. There is obtained 220 parts (77%) of2,2-dicyano-1-[2-(l-alpha-bromopyridinium) ethoxy] ethenolate in theform of white prisms, M. P. 168-170 C.

Anal.Calcd. for CuHsNaBrOz: C, 44.92; H, 2.74; N, 14.29. Found: C,44.83; H, 3.01; N, 14.37, 14.34.

EXAMPLE VIII EXAMPLE IX A solution of parts of pyridine and 100 parts ofdicyanoketene trimethylene acetal (alternately namedZ-dicyanomethylene-1,3-dioxane) in 265 parts of tetra-. hydrofuran isallowed to stand overnight at room temperature. The solid which forms iscollected on a filter,

washed with ether and recrystallized from water. There 1 is obtainedparts (91%) of 2,2-dicyano-1-[3-(1- pyridinium)propoxy]ethenolate in theform of white plates, M. P. 173174 C. t

pink precipitate which forms is collected on a filter,

washed with water and recrystallized from acetone-water.

There. is obtained 5 g. of 1-(Z-hydrQXyethyDpyridinium Anal.Calcd. forC12H11Na02: c, 62.87; H, 4.84;,N, 18.33. Found: C, 62.90, 63.03; H,4.92," 5.10; N, 18.49, 18.52.

EXAMPLE X A mixture of 100 parts of tctracyanoethylene, 246 parts ofpyridine, and 279 parts of distilled ethylene glycol is heated on asteam bath until solution is complete. The black mixture is allowed tostand several hours at room tempertaure and a dark precipitate forms.This solid material is collected on a filter, washed with water and thenrecrystallized from water to give 50 parts (30%) of 2,2-dicyano- 1[2-(l-pyridinium)ethoxylethenolate, M. P. 201-202 C. A mixed meltingpoint with the product of Example V is not depressed.

It will be understood that the above examples are merely illustrativeand that the present invention broadly comprises the new class ofcompounds, 2,2-dicyano-l- [(trisubstitutedammonium)alkoxylethenolatesand the process of preparing such ethenolates by reacting a2-dicyanomethylene cyclic 1,3-acetal with at least a substantiallymolecular equivalent amount of a tertiary amine.

The Z-dicyanornethylene 1,3-acetals used in the preparation of' theethenolates of this invention are alternately termed Z-dicyanomethylene1,3-dioxacycloalkanes. They comprise 2-dicyanomethylene-1,3 dioxolanehaving the formula:

and Z-dicyanomethylene-1,3-dioxane having the formula:

and their hydrocarbon-substituted derivatives in which any of thehydrogens at the 4- and 5- positions of the dioxolane or the 4-, 5-, and6- positions of the dioxane are replaced by hydrocarbon radicals,including compounds in which any two of these hydrogens are replaced bythe points of attachment of a hydrocarbon diradical. Illustrative ofsuch hydrocarbon-substituted derivatives are: 2 dicyanomethylene 4methyl 1,3 dioxolane; Z-dicyanomethylene 4,4,5,5 tetraethyl 1,3dioxolane; Z-dicyanomethylene 4,5 di n propyl 1,3 dioxolane; and 2dicyanomethylene-4,4,6-trimethyl 1,3 dioxane.

5 amines. The tertiary amines include both compounds in which thetrivalent nitrogen is bonded to three separate carbon atoms and those inwhich the trivalent nitrogen is singly bonded to one carbon atom anddoubly bonded to another carbon atom as in pyridine, quinoline, N-ben-10 zylideneaniline, N-l-ethylbutylidiene-p-toluidine, and the like. Itis essential in order to separate the ethenolates with facility that thetertiary amine be present in at least substantially molecular equivalentamounts and it can be present in considerable excess.

The process of this invention can be carried out under very mildconditions since the reaction takes place readily at room temperatureand at atmospheric pressure. It is ordinarily convenient to provide fordissipation of the heat of reaction by carrying out the process in thepresence of a liquid diluent. Such a diluent is preferably a solvent forthe reactants and/or the products and can be water, an aliphaticalcohol, a ketone or a cyclic ether. However, a liquid diluent is notessential to the process of the invention. When the tertiary amine to beemployed is a liquid, for example, pyridine, it sufiices to dissolve theZ-dicyanomethylene 1,3-acetal in the amine and allow the reaction toproceed without the presence of other additives.

The 2,2-dicyano-l-l (trisubstitutedammonium)alkoxy] ethenolates of thisinvention can be represented by the following formula:

NC\ o- NC 0-(cR IA3 where n is'2 or 3, the Rs may be hydrogen,hydrocarbon radicals or any two of them may represent points of at- 40tachment for a hydrocarbon diradical, and the As represent attachment ofthree bonds of nitrogen to two or three separate carbon atoms inaliphatic, aralkyl or aromatic radicals (including diradicals which forma ring with the nitrogen as a heteroatom) When equivalent amounts of thestarting materials indicated in Table I are employed in the process ofExample IV, the indicated 2,2-dicyano-l-I(trisubstitutedammonium)alkoxy] ethenolates are obtained.

Table I Starting Materials Product 2-Dieyanomethylene 1,3-AcetalTertiary Amine 2,2-Dicyano-1-[(trisubstitutedammonium)alkoxy] ethenolateNO\ /0C2 NCH:CH3 NC /O- /C=C\ /CH: ([IH: CH: ==C\ No 0-011, on, H: NCoon2)3;ir on2-om dieyanoketenettriml' ethylene CH; CH CH ace aN-ethylpiperidine CH2 CH2 [2-dicyanomethylene-l,3-d.ioxane] \ofi 2dieyanoketene 1,2diethyl-L2- diisopropylethylene acetal{2-dicyanoethylene-4,5-diethyl-4,5- diisopropyl-1,3-dioxolane]N-benzylideneaniline2,2-dicyano-1-[3-(N-ethylpiperidinium)-propoxy]ethenolate2,2-dicyano-1-[2-(N-benzylideneanilinium)-1-ethyl-l,2-diisopropylbutoxy] ethenolate Table .I-Continued Starting MaterialsProduct Dicyanoketene Cyclic Acetal Tertiary g gg2,2-Dicyano-1-[(trisubstitutedammonium)alkoxy] ethenolate E CH CH 7 CNNC 0 o o-cfi CH a i N\ 0:0 CHz-CHr-CN CHzCHz-CN NC OCH-CH-N NC OCH OHCHz-CHzOH CH: CH: CHr-CHr-CN di-(beta-eyanoethyD- CH=C CH;CH:OHdicyanoketene 1,2-(4-cyclol1exene)ylene ethanolamine acetal2,2-dicyano-1-[6 (di-[beta-cyauoethyH-beta-hydroxyethylammomum)-3-cyclohexeneoxy] ethenolate[3,4-(dicyanomethylene)-methylenedioxy-l-cyclohexene] The2,2-dicyano-l-[ (trisubstitutedammonium) alkoxy] ethenolates of thepresent invention are useful as antistatic agents for hydrophobictextiles; For exampel a tricot-knit fabric of Dacron polyester fiber isdipped in a hot 1% aqueous solution of2,2-dicyano-l-[2-(triethylammonium)ethoxy] ethenolate. Excess solutionis removed by centrifuging and the fabric is dried. Friction of thistreated fabric against wool, hair or plastic materials producessubstantially no accumulation of static charge, whereas a control pieceof the same fabric in untreated form when subjected to similar frictionbecomes charged with static electricity so that it fails'to drapeproperly and tends to attract particles of dirt and 'dust to the fabric.7

As many apparently widely different embodiments of this invention may bemade without departing from the spirit and scope thereof, it is to beunderstood that the invention is not limited to the specific embodimentsthereof except as defined in the appended claims.

The invention claimed is:

1. A 2,2-dicyano-1-[ (trisubstitutedammonium) alkoxy] ethenolate. i

2. A 2,2-dicyano-l-[2-(trisubstitutedammonium)ethoxy] ethenolate. 1 I

3. A 2,2-dicyano-l-[3-(trisubstitutedammonium)pro poxy] ethenolate. r V

i 4. A 2,2-dicyano-1-[(trialkylsubstitutedammonium)al koxy] ethenolate.v

5. A 2,2-dicyano-1-[2-(trialkylsubstitutedammonium)- ethoxy] ethenolate.

6. 2,2 Dicyano 1 [2 (t' ethylammonium)ethoxy] ethenolate. r V

7. Process of preparing a 2,2-dicyano-1-[(trisubstitutedammonium)alkoxy] ethenolate which comprises reacting a Z-dicyanomethylene cyclic1,3-acetal with at least a substantially molecular equivalent amount ofa tertiary amine.

8. Process as set forth in claim 7 wherein said reaction a is carriedout in an inert liquid diluent under substantially atmosphericconditions.

No references cited.

1. A 2,2-DICYANO-1-((TRISUBSTITUTEDAMMONIUM) ALKOXY) ETHENOLATE. 7.PROCESS OF PREPARING A 2,2-DICYANO-1-((TRISUBSTITUTEDAMMONIUM)ALKOXY)ETHENOLATE WHICH COMPRISES REACTING A 2-DICYANOMETHYLENE CYCLIC1,3-ACETAL WITH AT LEAST A SUBSTANTIALLY MOLECULAR EQUIVALENT AMOUNT OFA TERTIARY AMINE.